C-alkyloxy substituted tert.-butyl amine as lubricating oil detergent

ABSTRACT

Tert.-butyl amines having an alkyl group of at least 10 carbon atoms bonded through a heteroatom to carbon find use as detergents in lubricating oils.

I Umted States Patent 51 3,640,855 Bakker 1 Feb. 8, 1972 [54] C-ALKYLOXYSUBSTITUTED TERT.- 5 References cited BUTYL AMINE AS LUBRICATING OILUNITED STATES PATENTS DETERGENT 3,309,316 3/1967 McNinch et a1...252/51.5 A [721 Nm'aas Cahf' 3,340,192 9/1967 Henley ..252/s1.5

73 A h I 1 Ss'gnee g zgfg Company San Fran FOREIGN PATENTS ORAPPLICATIONS 22] Filed: Sept. 6, 1968 1,138, 2 6/1957 France Appl'758,123 Primary ExaminerDaniel E. Wyman Assistant Examiner-W. Cannon[52] us. Cl ..252/32.7, 252/46.7, 252/515, A rn y-A L- w, h n and I.Rowland 260/584 51 1m.c1 ..C10m 1/38,C10m l/32,Cl0m 1/20 57 ABSTRACT[58] Field of Search ..252/51.5, 46.4, 32.7 E, 46.7;

260/584 C Tert.-butyl ammes havmg an alkyl group of at least 10 carbonatoms bonded through a heteroatom to carbon find use as detergents inlubricating oils.

5 Claims, No Drawings C-ALKYLOXY SUBSTITUTED TERT.-BUTYL AMINE ASLUBRICATING OIL DETERGENT BACKGROUND OF THE INVENTION l. Field of theInvention An accelerated improvement in performance of lubricating oilshas resulted from the addition to the lubricating oils of a I variety ofnew additives. One of the most important additives has been the ashlesslubricating detergent. These detergents which are effective over a widerange of conditions-the high temperatures of the diesel engine to thecyclical and lower temperatures of the automobile internal combustionenginehave provided greatly improved performance in the dispersion inthe oil of deposit-forming materials.

Efforts are being continually made to further reduce the deposits.Deposits comprise not only black material, but a light-colored thin filmreferred to as varnish." This resinous material or lacquer is onlydifficulty prevented. Since the mechanisms for sludge formation andvarnish formation are not the same, ashless detergents are notequivalent in maintaining the dispersion of sludge and the removal orprevention of varnish deposits.

2. Description of the Prior Art US. Pat. No. 1,888,023 teaches the useof tert.-alkyl amines for color stabilizers. US. Pat. No. 2,832,74lteaches the use of tert.-amines for color stabilizers in bright stock.

SUMMARY OF THE INVENTION Beta-substituted primary amines bonded to atert.-carbon atom, wherein the beta-substituent is an oil solubilizinghydrocarbon group bonded to the tert.-alkyl group through a heteroatom,are used as detergents and dispersants in lubricating oils to preventsludge deposition and varnish formation.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The compositions of thisinvention will, for the most part, have the following formula:

wherein R is an oil solubilizing group of from l to 30 carbon atoms,usually aliphatic, either branched or straight chain, and having from 0to I site of olefinic unsaturation, usually saturated aliphatic andstraight chain. R and R are lower alkyl of from I to 3 carbon atoms,more usually lower alkyl of one carbon atom, i.e., methyl. X is aheteroatom, either oxygen, nitrogen (the third valence of nitrogen beingsatisfied by hydrogen or hydrocarbon of from one to six carbon atoms) orsulfur. If sulfur, the sulfur may be present in its reduced state i asthioether, or in its oxidized state as the sulfoxy or sulfone.

Preferred compositions will have R and R as methyl and R as alkyl offrom 12 to 28 carbon atoms.

The hydrocarbon group of the beta-substituent may be bonded to theheteroatom, either terminally or internally. The carbon atom bonded tothe heteroatom may be primary, secondary, or tertiary. The hydrocarbongroup may be a single hydrocarbon group or a mixture of hydrocarbongroups, derived either from synthetic or natural sources. Thehydrocarbon group may be obtained by the low-pressure polymerization ofolefins of from two to five carbon atoms, e.g., ethylene, propylene,butene-l, isobutylene, etc., using aluminum alkyl catalysts, bywax-cracking, etc.

Illustrative compositions included in the above formula arel-(N-octadecylamino)-2-amino-2-methylpropane, l -(N-tetradecyl-N-ethylamino)-2-amino-2-methylpropane, l-(N-eicosyl-N-methylamino)-2-amino-2-methylpropane,l-(N-octacontylamino)-2-amino-2-methylpropane,l-(N-octadecylamino)-2-amino-2-methylbutane, l-(N-tetracontyl-N-phenylamino)-2-amino-Z-methylbutane, l-octadecylthio-Z-amino-2-methylpropane, l-octadecylthio-2- amino-2-ethylbutane,l-tetradecylthio-2-amino-2-methylpropane,l-hexadecylthio-2-amino-2-methylpropane. l-octyldecylsulfinyl-Z-amino-Z-methylpropane, l-hexadecylsulfinyl-2-amino-2- methylbutane,l-hexadecysulfinyl-2-amino-2-methylpropane,l-hexadecylsulfonyl-2-amino-2-methylpropane,l-eicosylsulfonyl-2-amino-2-methylpropane, l-docosylthio-Z-amino-Z-methylpropane, l-eicosythio-2-amio-2-methylpropane,leicosyloxy-Z-amino-2-methylpropane, l-pentapropyleneoxy-2-amino-2-methylpropane, l-tetraisobutyleneoxy-2-amino-2- methylpropane,l-pentaisobutyleneoxy'2-amino-2-methylbutane, l-(Calkyloxy)-2-amino-2-methylpropane,l-pentapropylenethio-Z-amino-2-methylpropane.

The various subgenera will now be considered based on variations in theheteroatom which is bonded to term-alkyl primary amine. The firstsubgenus is that in which nitrogen is the heteroatom.

The compositions having nitrogen as the heteroatom will, for the mostpart, have the following formula:

wherein R, R and R are as previously defined, and A is a hydrocarbongroup of from one to six carbon atoms or hydrogen, more usually ahydrocarbon group of from one to three carbon atoms or hydrogen.

Illustrative groups for A are methyl, ethyl, propyl, phenyl,cyclopentyl, etc.

The nitrogen compositions can be readily prepared by combining anitroalkane, wherein the nitro is bonded to a secondary carbon atom,with formaldehyde and the desired amine. The course of the reactionfollows the following equation:

The nitro derivative may then be reduced to the primary amine. Thisreaction is described in U.S. Pat. No. 2,413,248 and in J. Am. Chem.Soc. 70 I846 (I948).

The composition having sulfur as its heteroatom will, for the most part,have the following formula:

wherein R, R and R have been defined previously and n is a number from 0to 2.

The thioether can be prepared by displacement on the appropriateoxazoline with the desired alkyl mercaptan. Or, the thiol acid can beused, and the resulting mercaptan added to an olefin by knownprocedures, The displacement of the oxazoline by a mercaptan or athiolester is described for the thiolester in US. Pat. No. 3,351,644.For the sulfinyl or sulfonyl functionalities, the sulfur may then beoxidized to the desired extent using peroxidic materials.

The compositions having oxygen as their heteroatom will, for the mostpart, have the following formula:

wherein R, R and R are as defined previously.

These compositions are readily prepared by reacting the alkali metalsalt of a C-hydroxy substituted tert.-alkyl amine with an aliphatichalide to obtain the desired oxy ether. The

reaction may be carried out in an inert solvent such as an ether ornitrile, e.g., acetonitrile, and at temperatures in the range of about50 to 100 C.

EXAMPLES The following examples are offered by way of illustrating andnot by way of limitation.

EXAMPLE 1 Into a reaction vesselwas introduced 45.5 g. of 2-amino-2-methyl-l-propanol and 500 cc. of tetrahydrofuran. To the mixture wasthen added incrementally 24 g. of sodium hydride as a 50 weight percentslurry in oil. The mixture was refluxed for 1 hour, cooled and 166.5 g.of n-bromo-octadecane added. After refluxing the mixture for 1 hour, amajor portion of the tetrahydrofuran was removed by distillation atatmospheric pressure. The residue was cooled to room temperature,frltered and then strippedon a steam plate. The product was distilled invacuo, collecting the fraction boiling at 160-185 C. at 0.2 mm. Hg. Theproduct weighed 100 g.

The product was titrated, yielding a molecular weight of 370;theoretical molecular weight of 341. Analysis: %N, 3.58. A vapor phasechromatograph of the product showed only a minor amount of materialother than a single product.

As already indicated, the compositions of this invention find use asdetergents and dispersants in lubricating oils and are found to beeffective under a wide variety of conditions; not only under the hotconditions of the diesel engine, but the much more variable temperatureconditions of the automobile engine.

The compositions of this invention may be formulated with variouslubricating fluids (hereinafter referred to as oils) which are eitherderived from natural or synthetic sources. Oils generally haveviscosities of from about 35 to 50,000 Saybolt Universal Seconds (SUS)at 100 F.

. Among natural hydrocarbonaeeous mineral oils are paraffin base,naphthenic base, asphaltic base and mixed base oils.

Illustrative of synthetic oils are hydrocarbon oils, such as polymers ofvarious olefins, generally from two to eight carbon atoms and alkylatedaromatic hydrocarbons, and nonhydrocarbon oils, such as polyalkyleneoxides, aromatic ethers, carboxyl esters, phosphate esters, and siliconesters. The preferred media are the hydrocarbonaceous media, bothnatural and synthetic.

The above oils may be used individually or together whenever miscible ormade so by the use of mutual solvents.

When the detergents of this invention are compounded with lubricatingoils for use in an engine, the detergents will be present in at leastabout 0.1 weight percent and usually not more than 20 weight percent,more usually in the range of about 1 to weight percent. The compoundscan be prepared as concentrates due to their excellent compatibilitywith oils. As concentrates, the compounds of this invention willgenerally range from about 10 to 70 weight percent, more usually fromabout to 50 weight percent of the total composition.

A preferred aspect in using the compounds of this invention inlubricating oils is to include in the oil from about 1 to 50 mmJkg. of adihydrocarbyl phosphorodithioate, wherein the hydrocarbyl groups arefrom about four to 36 carbon atoms. Usually, the hydrocarbyl groups willbe alkyl or alkaryl groups. The remaining valence of thephosphorodithioate will usually be satisfied by zinc, butpolyalkyleneoxy or a third hydrocarbyl group may also be used.(Hydrocarbyl is an organic radical composed solely of carbon andhydrogen which may be aliphatic, alicyclic, or aromatic or combinationsthereof.)

Other additives may also be included in the oil such as pour pointdepressants, oiliness agents, antioxidants, rust inhibitors, etc.Usually, the total amount of these additives will range from about 0.1to 10 weight percent, more usually from about 0.5 to 5 weight percent.The individual additives may vary from about 0.01 to 5 weight percent ofthe composition.

in order to demonstrate the excellent effectiveness of the compounds ofthis invention as detergents and dispersants in lubricating oils, anumber of the compounds were tested in a l-G Caterpillar test (MIL-L45199 conditions). The oil used was a Mid Continent SAE 30 oil and 12mmJkg. of zinc di(alkylphenyl) phosphorodithioate the alkyl groups werepolypropylene of about 12 to 15 carbon atoms) was included.

The following table indicates the particular derivative used, the amountused, the time for which the run was carried out and the results. Alsoincluded for comparison are the results for the base oil containing onlythe phosphorodithioate. The rating of groove deposits is based on arange of 0 to 100, being completely filled grooves. The rating for landdeposits is based on a range of 0 to 800, 800 being completely black.

TABLE 1 Additive Wt. Groove Deposits Land Deposits Groove deposits-basedon 0 to 100, 100 being completely filled.

Land deposits-based on O to 800, 800 being completely black.

VARNISH TEST An apparatus is employed comprising an aluminum block7%X4Xl'7z in. with an oil outlet, which is fitted with heating means anda thermocouple. A glass cover is provided for the aluminum block whichcompletely encloses the area over the aluminum block, except for thevarious inlets and outlets to be described. Used in the determination ofvarnish are piston alloy plates 4% 1% 3/l6 in. having a slope of l in.in 10 in. The alloy plate is carefully cleaned and repeatedly washedwith aliphatic solvents, dried and weighed. The test plate is thenintroduced into the glass enclosure and firmly affixed to the aluminumblock.

An oil solution is prepared comprising g. of the test oil, 60 g. of aFCC heavy oil, 2 g. of L-4 catalyst (a metal naphthenate solution whichhas a metals concentration which is deemed to be present in usedcrankcase oil of an L-4 Chevrolet Engine Test), (see U.S. Pat. No.3,320,163, issued May 16, 1967) and 2 g. of water. The test oil was aMid-Continent SAE 30 base oil and contained 3 weight percent of the testadditive and 1.5 weight percent of the commercial additive. The mixtureis homogenized in a Waring Blender for 2 min. at full power. Theenclosed area is then flushed with oxygen and pressured to 5 in.(di-(n-buty)phtalate).

The oil solution is continuously agitated and dripped onto the testplate at a rate of one drop per second. During the test, the oil mixtureis maintained at 66 C. and the plate is also maintained at the sametemperature. When the addition is begun, the oxygen supply to theenclosure is closed and 100 cc. of NO in introduced into the enclosure.After 2 min., the oxygen supply is opened and the system pressurized to6 in. (di-(n-butyDphthalate). The addition of NO is repeated seven timesat 4-min. intervals.

The run is continued for 1 hr. at a constant temperature of 66 C. withthe oil continuously recirculating. That is, the oil is returned fromthe enclosure to the main body of the oil. At the end of the hour, thetest plate is allowed to cool. It is then washed carefully free of oilwith hexanes, dried and weighed. The results are as follows reported asmilligrams deposit:

TABLE I1 Additive Deposit, mg. Ex. 1 3.5 A 104.8

Commercial polyisobutenyl auccinimide of alkylene polyamine(polyisobutenyl 1,000 mol wt.)

In order to further demonstrate the effectiveness of the subjectcomposition on reducing piston varnish, a test was carried out whichwill be referred to as the Ford Varnish Engine Test. A highly compoundedoil was used having the following formulation: 3 weight percent of theexemplary composition of Example I; 50 mm./kg. calcium as a calciumcarbonate overbased calcium mahogany sulfonate; l5 mmJkg. of zinc0,0-dialkyl phosphorodithioate (alkyl of from four to six carbon atoms).The oil used was a mixture of Sunray BX 250 neutral oil and Sunray DX150 bright stock in a 6.16/1 weight ratio.

The test was carried out with a six-cylinder Ford engine having a 240cubic inch displacement. The engine conditions are the same as thecyclic conditions of the ASTM sequence VB test. The engine conditionsare stressed by using a dirty" fuel which is comprised of 30 volumepercent of a FCC heavy cut having a boiling range of from 235 to 424 F.with 70 volume percent of a commercial regular grade gasoline. The fuelhas 2 mil. per gallon of lead and approximately 0.1 weight percentsulfur. The engine run is carried out for 60 hrs.

The piston varnish rating was 6.5 based on a rating of 0 to 10, beingclean. This compared favorably to commercially available ashlessdetergents in being a comparable varnish ratmg.

It is evident from the above results that the compounds of thisinvention, which are relatively simple, are surprisingly effective undera wide variety of conditions in internal combustion engines asdetergents and dispersants. Not only do they maintain sludge dispersedin lubricating oil, but they effectively prevent varnish deposits.Because of their detergent capabilities, the composition may also beused in fuels and as emulsifiers with asphalt and in specialty oils.

l claim:-

I. A lubricating oil composition having an oil of lubricating viscosityin lubricating amounts and from 0.1 to weight percent of a compound ofthe formula:

wherein R is an oil solubilizing hydrocarbon group of from 10 to 30carbon atoms, R and R are lower alkyl of from one to three carbon atomsand X is oxygen.

2. A lubricating oil composition according to claim 1, wherein R isalkyl of from 12 to 28 carbon atoms.

3. A lubricating oil composition according to claim 1. wherein thecomposition of the formula is present in from 0.l to 20 weight percentand said lubricating oil composition has from 1 to 50 mm./kg. of aphosphorodithioate selected from the group consisting ofpolyalkyleneoxy-dihydrocarbyl, zinc dihydrocarbyl and trihydrocarbylphosphorodithioates wherein the polyalkyleneoxy and hydrocarbyl groupscontain four to 36 carbon atoms.

4. A lubricating oil composition according to claim 1 wherein R and Rare methyl.

5. A lubricating oil composition according to claim 1 wherein saidcompound is present in from 0.1 to 20 weight percent.

2. A lubricating oil composition according to claim 1, wherein R isalkyl of from 12 to 28 carbon atoms.
 3. A lubricating oil compositionaccording to claim 1, wherein the composition of the formula is presentin from 0.1 to 20 weight percent and said lubricating oil compositionhas from 1 to 50 mm./kg. of a phosphorodithioate selected from the groupconsisting of polyalkyleneoxy-dihydrocarbyl, zinc dihydrocarbyl andtrihydrocarbyl phosphorodithioates wherein the polyalkyleneoxy andhydrocarbyl groups contain four to 36 carbon atoms.
 4. A lubricating oilcomposition according to claim 1 wherein R1 and R2 are methyl.
 5. Alubricating oil composition according to claim 1 wherein said compoundis present in from 0.1 to 20 weight percent.